public class Text4 {
    // 137.只出现一次的数字II
    public int singleNumber(int[] nums) {
        int ret = 0;

        for (int i = 0; i < 32; i++) {
            int sum = 0;
            for (int x : nums) {
                if (((x >> i) & 1) == 1)
                    sum++;
            }

            sum %= 3;
            if (sum == 1)
                ret |= (1 << i);
        }

        return ret;
    }
}
